【摘要】 输电线路结冰对电网安全构成严重威胁。为实现冰冻早期预警与在线冰厚测量，需考虑结冰初期粗糙冰层对超声回波信号的影响。本文采用正弦等效粗糙度模型简化冰层截面，运用PZFlex软件研究不同粗糙结构尺度对超声脉冲回波信号的影响。引入冰层-空气界面反射系数表征小尺度粗糙度。研究发现脉冲回波信号衰减主要受粗糙结构高度主导：随着冰层表面粗糙度增大，界面反射系数逐渐降低；当粗糙度超过临界值时，反射系数与粗糙度呈现无关性。以反射系数阈值0.25为基准，确定了不同中心频率激励信号下粗糙度的有效测量范围。建立了反射系数与粗糙冰层的关联，实现了利用超声脉冲回波技术对粗糙冰层进行定量识别。该研究为输电线路冰厚精确测量提供了技术依据。更多还原

【Abstract】 Ice accretion on transmission lines poses a severe threat to the safety of power grids. To achieve early icing warning and online ice thickness measurement, it is necessary to consider the effect of the rough ice layer on ultrasonic echo signals during the early icing stage. This study applied a sinusoidal equivalent roughness model to simplify the ice layer profile, and used PZFlex to numerically analyze the effects of the rough structure scale on the ultrasonic pulseecho signals. The reflection coefficient of the ice-air layer interface was introduced to characterize small-scale roughness. It is found that the attenuation of pulse-echo signals is dominant by the height of rough structure. As the roughness upper ice layer increases, the interface reflection coefficient gradually decreases. When the roughness exceeds the critical value, the reflection coefficient shows independent with roughness. As the threshold of reflection coefficient is set as 0.25, the effective measurement range of roughness under different center frequencies of excitation signal sources is determined. The relationship between the reflection coefficient and roughness upper ice layer is established, enabling the quantitative identification of rough ice layer using the ultrasonic pulse-echo technique. The research can provide a technical basis for the accurate measurement of ice thickness above transmission lines.更多还原